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Private member DiscussionTools and Jigs

Measured drawing and assembly for Proper Variable Radius Sanding Jig

Doug Proper designed a sanding jig that supports variable concave and convex curves, described in the following Loothgroup article: https://loothgroup.com/post-imgcap/the-variable-radius-sander/ I built one and am impressed with how it facilitates preparing bridges, braces and also allows tracing any radius using the chord formula. I made a rough measured drawing and assembly guide to share, with Doug's blessing. First step, ma…

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Ian Davlin
Thank you John !
Private member DiscussionRepair and Restoration

Fret levelling: How low is too low?

I finished levelling frets on a mandolin last week, and was surprised that the frets with the worst divots worked down to .020" Had I known that I'd go that low, I might have replaced them, but it's hard to measure divot height, especially those caused by thin strings. I haven't seen much discussion on standards for fret height or guidelines to know at what point should I switch from levelling to replacement. What standards are peop…

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I’ve found for most guitar players anything below .030” starts to get into refret territory. Might be different for mandolins though, I don’t work on many of those. I have a client that loves the fret…
Private member DiscussionAcoustic Repair

Advice on getting this 50s parlor nylon back into good shape?

Hi all, I'm new here. I've been playing guitars for ~15 years and recently started as a technician at a music production school in London, where part of my job is maintaining the guitars. I picked up this 50s parlor nylon the other day and it's in bad shape but I don't know how to go about repairing it. The main issue is the bridge. The guitar was kept high strung and the bridge has twisted and lifted off slightly at the base. T…

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So now put the iron on low, heat the bridge for at least 5 minutes, then take it and the insulating cardboard off, and see if you can begin to work palette knives under the bridge. If it's not relativ…
Private member DiscussionFinish Repair

Supertone with ? overspray - need advice on how to refinish

I am restoring an old Supertone with a thickened and heavily alligatored finish. The finish softens quickly with acetone, and it looks like it has had an overspray. I would like to keep the staining on the oak back and sides, and to preserve the decal on the headstock. The top I would like to strip and sand. The questions are: 1. What more do I need to know about the finish? 2. How should I remove the finish or at least thin/smooth…

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Ian Davlin
I don’t see much evidence of overspray. The headstock looks to be in decent shape. I’d just leave it unless the finish is actively falling off. One thing you might try on the top before refin is Mohaw…
Private member DiscussionAcoustic Repair

how to touch this up?

I have repaired numerous top crack on this instrument built by a customer at a guitar building camp. The bridge was off and warped. That has been addressed. After gluing with hide glue and splining the crack these top two did not closed as much as I would have liked. The bigger is about 1/32 at the widest and the other about 1/64. The crack is tight at the bottom. If I can help it I would like to fill it rather than spline it as I have…

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I am pretty good at touch up on darker to med woods and air brushing some solid color touchups on electrics but as you said spruce tops with gloss are near impossible. I was hoping to maybe clean it…
Private member DiscussionAcoustic Builds

New Acoustic Build - Having trouble

Hi all. Brand new member. I’ve been building a classical guitar via kit from LMI for a couple of years now. I keep putting it off but recently became motivated to get back to it. Unfortunately LMI is out of business so I now have no one to go to to ask questions. I’m at the stage where I’m putting the sides together in the form. I followed the dimensions for the form based on the plans as I measured them, but the sides overlap pretty ba…

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Structurally you are fine. When you glue this up (this is important), make sure your sides are clamped in the form VERY snug so there are no gaps between the sides and the forms. This will leave the…
Private member DiscussionFinish New Builds

Aging Toner on a Sitka Spruce Top

I'm fast approaching the finish coating of 2 acousitcs. The sitka spruce tops are really bright. I'd like to tone them down a little and have been scouring the web for methods. Seems like adding amber toner in either the sand sealer or more likely the first set of nitro lacquer coats might be the the ticket. I see Stewmac has a Colortone stain called "Vintage Amber" that can be mixed into the nitro. Anybody have expirience with this pro…

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Hi Gerry, I recommend spraying a sealer chow it a light scuff and then one more sealer coat. If you are using lacquer, thin some 50% by volume and add TransTint or Colortone. Same dye and some of the…
Private member DiscussionAcoustic Builds

Temp Dovetail Holder for Finishing

Has anyone developed, or know of for sale, a fixture that can be installed in an acoustic body (dovetail neck) during finishing? I'm approaching the spraying stage of my build and would like to be able to have a "handle" on the body that I can use to hold & hang the body during that process. Regards,

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If you haven't settled in on anything yet, I might suggest the Total Vise Small-Shop Finishing Station https://dev2.loothgroup.com/sponsor-post/the-small-shop-luthier-finishing-station/ Its much more v…
Private member DiscussionFinish Repair

Airbrush recommendations

Hello, Apologies if this has been answered before, I couldn’t find any posts covering it. I’m looking to get started with an airbrush for small finish repairs. AI is telling me to get a Fengda 186 with 3L tank and a Harder & Steenbeck brush (not cheap!). But would appreciate recommendations for a budget setup from actual human people also. Thanks!

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most cheap ones will do you fine, what medium are you using? Nitro? 2k? Water based? 1k? you probably don't need to view more expensive options unless you're looking to get into detailed work. Iwata…